The invention pertains to atomic layer deposition methods.
Atomic layer deposition (ALD) is recognized as a deposition technique that forms high quality materials with minimal defects and tight statistical process control. Even so, new deposition precursors are sought that may be particularly suited to ALD. ALD of aluminum nitride films has been accomplished with known precursors comprising aluminum alkyls, such as trimethyl aluminum, triethyl aluminum, and tributyl aluminum. However, the known precursors can be pyrophoric or require other special handling that complicates the ALD process.
Accordingly, a need exists for ALD precursors of aluminum-containing films that allow simplified processing.
According to one aspect of the invention, an aluminum-containing material deposition method includes depositing a first precursor on a substrate in the substantial absence of a second precursor, the first precursor exhibiting gas phase reactivity with the second precursor. The first precursor can contain a chelate of Al(NR1R2)x(NR3(CH2)zNR4R5)y or Al(NR1R2)x(NR 3(CH2)zOR4)y; where x is 0, 1, or 2; y is 3xe2x88x92x; z is an integer from 2 to 8; and R1 to R5 are independently selected from among hydrocarbyl groups comprising 1 to 10 carbon atoms with silicon optionally substituted for one or more carbon atoms. The method includes depositing the second precursor on the first deposited precursor in the substantial absence of a non-deposited first precursor. The second precursor can contain at least one of a nitrogen source and an oxidant. A deposition product of the first and second precursors can contain at least one of an aluminum nitride or an aluminum oxide. As an example, depositing the first precursor can occur at a temperature of from about 100xc2x0 C. to about 450xc2x0 C.
In another aspect of the invention, an ALD method includes chemisorbing a first precursor on a substrate in the substantial absence of a second precursor. The first precursor can exhibit gas phase reactivity with the second precursor. The first precursor can contain a chelate of Al(NR1R2)x(NR3(CH2)zNR4R5)y or Al(NR1R2)x(NR3(CH 2)zOR4)y; where x is 0,1, or 2; y is 3xe2x88x92x; z is an integer 2 to 8; and R1 to R5 are independently selected from among hydrocarbyl groups containing 1 to 10 carbon atoms with silicon optionally substituted for one or more carbon atoms. The method includes reacting the second precursor with the first chemisorbed precursor, the second precursor containing at least one of a nitrogen source and an oxidant. A reaction product of the first and second precursors includes at least one of an aluminum nitride or an aluminum oxide. As an example, the first precursor can be a liquid at a temperature of from about 20xc2x0 C. to about 100xc2x0 C. Also, the first precursor can be vaporized at a temperature of from about 25xc2x0 C. to about 150xc2x0 C. The first precursor can exhibit a vapor pressure of at least about 0.1 Torr at a temperature of from about 25xc2x0 C. to about 150xc2x0 C. The first precursor can exhibit a chemisorption rate of at least about 0.5 monolayers per second at 10xe2x88x924 Torr with a solid surface comprising an oxide having hydroxyl groups on the oxide surface, platinum, rhodium, iridium, titanium, TiN, TaN, TaSiN, TiBN, or silicon. The first precursor can further be non-pyrophoric.
According to further aspect of the invention, an ALD method includes chemisorbing a first precursor on a substrate at a temperature of from about 150xc2x0 C. to about 250xc2x0 C. in the substantial absence of the second precursor. The first precursor can exhibit gas phase reactivity with the second precursor. The first precursor can contain the chelate described above where z is an integer from 2 to 4 and R1 to R5 are independently selected from among hydrocarbyl groups containing 1 to 5 carbon atoms with silicon optionally substituted for one or more carbon atoms. The method includes reacting the second precursor with the first chemisorbed precursor at substantially the same temperature. The second precursor can contain at least one of a nitrogen source and an oxidant. A reaction product of the first and second precursors can contain at least one of AlN or Al2O3.
According to a still further aspect of the invention, an ALD method includes chemisorbing a monolayer of a first precursor on a substrate at a temperature of from about 100xc2x0 C. to about 400xc2x0 C. in the substantial absence of a second precursor. The first precursor consists essentially of Al(N(CH3)2)2(N(CH3)CH2CH2N(CH3)2) and the substrate contains at least one of metal oxide, platinum, titanium, and TiN. The first precursor is purged from over the substrate and a monolayer of a second precursor is reacted with the first chemisorbed precursor. The second precursor contains at least one of a nitrogen source and an oxidant. A reaction product of the first and second precursors contains at least one of AlN or Al2O3. The second precursor is purged from over the substrate and exposure and purging of the first and second precursors is successively repeated to form a capacitor dielectric layer.